Demonstrators among tens of thousands who protested about austerity in London on Saturday. Photograph: Mary Turner/Getty Images

The UK economy has been in difficulty since the 2008 financial crisis. Tough spending decisions have been needed to put it on the path to recovery because of the huge budget deficit left behind by the last irresponsible Labour government, showering its supporters with social benefit spending. Thanks to the coalition holding its nerve amid the clamour against cuts, the economy has finally recovered. True, wages have yet to make up the lost ground, but it is at least a “job-rich” recovery, allowing people to stand on their own feet rather than relying on state handouts.

First, let’s look at the origins of the deficit. Contrary to the Conservative portrayal of it as a spendthrift party, Labour kept the budget in balance averaged over its first six years in office between 1997 and 2002. Between 2003 and 2007 the deficit rose, but at 3.2% of GDP a year it was manageable.

More importantly, this rise in the deficit between 2003 and 2007 was not due to increased welfare spending. According to data from the Office for National Statistics, social benefit spending as a proportion of GDP was more or less constant at about 9.5% of GDP a year during this period. The dramatic climb in budget deficit from there to the average of 10.7% in 2009-2010 was mostly a consequence of the recession caused by the financial crisis.

First, the recession reduced government revenue by the equivalent of 2.4% of GDP – from 42.1% to 39.7% – between 2008 and 2009-10. Second, it raised social spending (social benefit plus health spending). Economic downturn automatically increases spending on many social benefits, such as unemployment benefit and income support, but it also increases spending on things like disability benefit and healthcare, as increased unemployment and poverty lead to more physical and mental health problems. In 2009-10, at the height of the recession, UK public social spending rose by the equivalent of 3.2% of GDP compared with its 2008 level (from 21.8% to 24%).

When you add together the recession-triggered fall in tax revenue and rise in social spending, they amount to 5.6% of GDP – almost the same as the rise in the deficit between 2008 and 2009-10 (5.7% of GDP). Even though some of the rise in social spending was due to factors other than the recession, such as an ageing population, it would be safe to say that much of the rise in deficit can be explained by the recession itself, rather than Labour’s economic mismanagement.

When faced with this, supporters of the Tory narrative would say, “OK, but however it was caused, we had to control the deficit because we can’t live beyond our means and accumulate debt”. This is a pre-modern, quasi-religious view of debt. Whether debt is a bad thing or not depends on what the money is used for. After all, the coalition has made students run up huge debts for their university education on the grounds that their heightened earning power will make them better off even after they pay back their loans.

The same reasoning should be applied to government debt. For example, when private sector demand collapses, as in the 2008 crisis, the government “living beyond its means” in the short run may actually reduce public debt faster in the long run, by speeding up economic recovery and thereby more quickly raising tax revenues and lowering social spending. If the increased government debt is accounted for by spending on projects that raise productivity – infrastructure, R&D, training and early learning programmes for disadvantaged children – the reduction in public debt in the long run will be even larger.

Against this, the advocates of the Conservative narrative may retort that the proof of the pudding is in the eating, and that the recovery is the best proof that the government’s economic strategy has worked. But has the UK economy really fully recovered? We keep hearing that national income is higher than at the pre-crisis peak of the first quarter of 2008. However, in the meantime the population has grown by 3.5 million (from 60.5 million to 64 million), and in per capita terms UK income is still 3.4% less than it was six years ago. And this is even before we talk about the highly uneven nature of the recovery, in which real wages have fallen by 10% while people at the top have increased their shares of wealth.

But can we not at least say that the recovery has been “jobs-rich”, creating 1.8m positions between 2011 and 2014? The trouble is that, apart from the fact that the current unemployment rate of 6% is nothing to be proud of, many of the newly created jobs are of very poor quality.

The ranks of workers in “time-related underemployment”, doing fewer hours than they wish due to a lack of availability of work – have swollen dramatically. Between 1999 and 2006, only about 1.9% of workers were in such a position; by 2012-13 the figure was 8%.

Then there is the extraordinary increase in self-employment. Its share of total employment, whose historical norm (1984-2007) was 12.6%, now stands at an unprecedented 15%. With no evidence of a sudden burst of entrepreneurial energy among Britons, we may conclude that many are in self-employment out of necessity or even desperation. Even though surveys show that most newly self-employed people say it is their preference, the fact that these workers have experienced a far greater collapse in earnings than employees – 20% against 6% between 2006-07 and 2011-12, according to the Resolution Foundation – suggests that they have few alternatives, not that they are budding entrepreneurs going places.

So, in between the additional people in underemployment (6.1% of employment) and the precarious newly self-employed (2.4%), 8.5% of British people in work (or 2.6 million people) are in jobs that do not fully utilise their abilities – call that semi-unemployment, if you will.

The success of the Conservative economic narrative has allowed the coalition to pursue a destructive and unfair economic strategy, which has generated only a bogus recovery largely based on government-fuelled asset bubbles in real estate and finance, with stagnant productivity, falling wages, millions of people in precarious jobs, and savage welfare cuts.

The country is in desperate need of a counter narrative that shifts the terms of debate. A government budget should be understood not just in terms of bookkeeping but also of demand management, national cohesion and productivity growth. Jobs and wages should not be seen simply as a matter of people being “worth” (or not) what they get, but of better utilising human potential and of providing decent and dignified livelihoods. Ways have to be found to generate economic growth based on rising productivity rather than the continuous blowing of asset bubbles.

Without a new economic vision incorporating these dimensions, Britain will continue on its path of stagnation, financial instability and social conflict.

Wage protesters marched over the greatest slump seen in real pay for 150 years, last Saturday, but it is the march of technological advance that is driving a wedge between the country’s highest and lowest paid workers